Week 02 :: Embedded Programming

What are the physical elements behind computing?



1. Browse through the datasheet for the RP2040

In the past, when I was trying to conceptualize a final project, I found it very difficult to imagine how electronics relate to space.


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Interacting with the physical microcontroller was the most intuitive way for me to gain information from the datasheet.

Notes from my learning:

GND refers to ground, which connects to the negative pole of the power supply. VCC stands for "voltage at common collector," and connects to the positive pole of the power supply.

The power supply for the RP2040 XIAO uses a USB to USB-c cable.

Pins located at the sides of the boards are mapped to different Inputs/outputs.

The small LED at the bottom of the front of the controller is called "Neopixel," and needs to be initiated as such in whatever code is loaded to the controller.



2. Writing a Program to Interact

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I have never tried to use a microcontroller before. Thankfully, TA Niklas Hagemann kindly walked through the basics of working with the RP2040 Xiao Seeed to a group of us architecture students.
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My first successful interaction came from trying example files, and simply alternating the color of the RP2040 Xiao's built-in LED.

Following the tutorial on seeed wiki, I also tried programming the RP2040 using Micropython:



3. Writing a program to communicate (remotely)

For a program to communicate remotely, I needed to learn how to use serial.available and serial.read, to read messages from the serial monitor. The initial structure of the script comes from ChatGPT, which was helpful for some of the syntax, but included references to raspberry pi peripherals that I was not using. After manually cleaning up the script, I was able to get what I want: the LED responds to text prompts from the user. Final code for this example can be found here.

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Typography graphic display using Grove 0.96" OLED peripheral.

Thinking toward the final project, I know that I need to learn more about interfacing different devices with the microcontroller. I chose a simple OLED display, and began researching how to use a breadboard and jumper wires.

My Arduino Sketch for this example was adapted from the Seeed Studio Wiki

To use the 0.96" OLED display, four wires are required. Connections are as follows:
XIAO GND == OLED GND
XIAO VCC == OLED VCC
XIAO Pin 4 == OLED SDA Pin XIAO Pin 5 == OLED SCL Pin



Toward the final project, I wanted to start scouting what devices I might need to use to reach my final project ambitions. Specifically, I want to find out what type of peripherals are required to send vibration pulses for haptic feedback.



4. Group Work
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Working with Nasibe Nur Dundar Arifoglu, we assembled a table comparing some development characteristics of working with the different microcontrollers.

Each of the datasheets for these microcontrollers have such vast amounts of information, there isn't necessarily one intuitive way to organize the categories. Several times, we would think a category was necessary, only to realize it didn't apply to the other boards and wasn't a useful criteria. This finding especially applied to pin layouts and peripheral compatibility.

As we looked through the options, I started to appreciate how we might work backwards from our final project to fine-tune our processor selection depending on what we need: lots of pins, low cost, processing speed, etc.